Electrohydraulic valve normally operating in pressure relief mode and configured to block fluid flow when actuated

ABSTRACT

An example valve includes: (i) a pilot seat member comprising a first channel and a second channel, a pilot seat, and a pilot sleeve portion comprising a pilot chamber and a cross-hole; (ii) a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring, wherein the pilot check member is configured to be subjected to fluid force of fluid in the second channel; and (iii) a solenoid actuator sleeve slidably accommodated about the pilot sleeve portion, wherein the solenoid actuator sleeve comprises a cross-hole and an annular groove, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to a second port of the valve, and the annular groove is configured to selectively fluidly couple the first channel to the second channel based on a position of the solenoid actuator sleeve.

BACKGROUND

A relief valve or pressure relief valve (PRV) is a type of safety valveused to control or limit the pressure in a system. Pressure mightotherwise build up and can cause equipment failure. The pressure isrelieved by allowing the pressurized fluid to flow out of the system toa tank or low pressure fluid reservoir. In some applications, a PRV canbe used to build pressure level of fluid up to a particular pressurelevel to operate a hydraulic system or component.

A PRV is designed or set to open at a predetermined setting pressure toprotect other components and other equipment from being subjected topressures that exceed their design limits. When the setting pressure isexceeded, the PRV becomes or forms the “path of least resistance” as thePRV is forced open and a portion of fluid is diverted to the tank. Asthe fluid is diverted, the pressure inside the system stops rising. Oncethe pressure is reduced and reaches the PRV's reseating pressure, thePRV closes.

SUMMARY

The present disclosure describes implementations that relate to anelectrohydraulic valve normally operating in pressure relief mode andconfigured to block fluid flow when actuated.

In a first example implementation, the present disclosure describes avalve. The valve includes: (i) a pilot seat member comprising: (a) afirst channel and a second channel, wherein the first channel is fluidlycoupled to a first port of the valve, (b) a pilot seat, and (c) a pilotsleeve portion comprising a pilot chamber and a cross-hole disposed inan exterior peripheral surface of the pilot sleeve portion; (ii) a pilotcheck member disposed in the pilot chamber and subjected to a biasingforce of a setting spring disposed in the pilot chamber, wherein thebiasing force acts in a distal direction to seat the pilot check memberat the pilot seat, wherein the pilot check member is configured to besubjected to fluid force of fluid in the second channel of the pilotseat member acting on the pilot check member in a proximal direction;and (iii) a solenoid actuator sleeve slidably accommodated about theexterior peripheral surface of the pilot sleeve portion of the pilotseat member, wherein the solenoid actuator sleeve comprises a cross-holedisposed in an exterior peripheral surface of the solenoid actuatorsleeve and an annular groove disposed in an interior peripheral surfaceof the solenoid actuator sleeve, wherein the cross-hole of the solenoidactuator sleeve is fluidly coupled to a second port of the valve. Whenthe valve is unactuated: (i) the cross-hole of the solenoid actuatorsleeve is aligned with the cross-hole of the pilot sleeve portion, and(ii) the annular groove fluidly couples the second channel to the firstchannel to enable generation of pilot flow from the first port to thesecond port when the fluid force overcomes the biasing force and thepilot check member is unseated. When the valve is actuated, the solenoidactuator sleeve and the annular groove move axially, thereby causing thesecond channel to be fluidly decoupled from the first channel andprecluding pilot flow from the first port to the second port.

In a second example implementation, the present disclosure describes ahydraulic system including a source of fluid; a reservoir; and a valvehaving a first port fluidly coupled to the source of fluid, and a secondport fluidly coupled to the reservoir. The valve comprises: (i) a pilotseat member comprising: (a) a first channel and a second channel,wherein the first channel is fluidly coupled to the first port of thevalve, (b) a pilot seat, and (c) a pilot sleeve portion comprising apilot chamber and a cross-hole disposed in an exterior peripheralsurface of the pilot sleeve portion; (ii) a pilot check member disposedin the pilot chamber and subjected to a biasing force of a settingspring disposed in the pilot chamber, wherein the biasing force acts ina distal direction to seat the pilot check member at the pilot seat,wherein the pilot check member is configured to be subjected to fluidforce of fluid in the second channel of the pilot seat member acting onthe pilot check member in a proximal direction; and (iii) a solenoidactuator sleeve slidably accommodated about the exterior peripheralsurface of the pilot sleeve portion of the pilot seat member, whereinthe solenoid actuator sleeve comprises a cross-hole disposed in anexterior peripheral surface of the solenoid actuator sleeve and anannular groove disposed in an interior peripheral surface of thesolenoid actuator sleeve, wherein the cross-hole of the solenoidactuator sleeve is fluidly coupled to the second port of the valve. Whenthe valve is unactuated: (i) the cross-hole of the solenoid actuatorsleeve is aligned with the cross-hole of the pilot sleeve portion, and(ii) the annular groove fluidly couples the second channel to the firstchannel to enable generation of pilot flow from the first port to thesecond port when the fluid force overcomes the biasing force and thepilot check member is unseated. When the valve is actuated, the solenoidactuator sleeve and the annular groove move axially, thereby causing thesecond channel to be fluidly decoupled from the first channel andprecluding pilot flow from the first port to the second port.

In a third example implementation, the present disclosure describes avalve. The valve includes: (i) a housing having a longitudinalcylindrical cavity therein and having a cross-hole disposed in anexterior peripheral surface of the housing; (ii) a main sleeve disposed,at least partially, in the longitudinal cylindrical cavity of thehousing, wherein the main sleeve includes a first port at a distal endof the main sleeve and includes one or more cross-holes disposed on anexterior peripheral surface of the main sleeve, wherein the cross-holeof the housing and the one or more cross-holes of the main sleeve form asecond port; (iii) a piston disposed within the main sleeve andconfigured to be axially movable therein, wherein the piston comprises amain chamber therein, and wherein the main chamber is fluidly coupled tothe first port via an orifice; (v) a pilot seat member comprising: (a) afirst channel and a second channel, wherein the first channel is fluidlycoupled to the first port, (b) a pilot seat, and (c) a pilot sleeveportion comprising a pilot chamber and a cross-hole disposed in anexterior peripheral surface of the pilot sleeve portion; (vi) a pilotcheck member disposed in the pilot chamber and subjected to a biasingforce of a setting spring disposed in the pilot chamber, wherein thebiasing force acts in a distal direction to seat the pilot check memberat the pilot seat, wherein the pilot check member is configured to besubjected to fluid force of fluid in the second channel of the pilotseat member acting on the pilot check member in a proximal direction;and (vii) a solenoid actuator sleeve slidably accommodated about theexterior peripheral surface of the pilot sleeve portion of the pilotseat member, wherein the solenoid actuator sleeve comprises a cross-holedisposed in an exterior peripheral surface of the solenoid actuatorsleeve and an annular groove disposed in an interior peripheral surfaceof the solenoid actuator sleeve, wherein the cross-hole of the solenoidactuator sleeve is fluidly coupled to the second port of the valve, andwherein the annular groove is configured to selectively fluidly couplethe first channel to the second channel based on a position of thesolenoid actuator sleeve.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects,implementations, and features described above, further aspects,implementations, and features will become apparent by reference to thefigures and the following detailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a cross-sectional side view of a valve in a pressurerelief mode, in accordance with an example implementation.

FIG. 2 illustrates a three-dimensional perspective view showing anarmature coupled to a solenoid actuator sleeve, in accordance with anexample implementation.

FIG. 3 illustrates a cross-sectional side view of a valve in aflow-blocking mode of operation, in accordance with another exampleimplementation.

FIG. 4 illustrates a cross-section side view of a valve having a manualadjustment actuator, in accordance with an example implementation.

FIG. 5 illustrates a cross-sectional side view of a solenoid tube, inaccordance with an example implementation.

FIG. 6 illustrates a hydraulic circuit using the valve shown in FIG. 4,in accordance with an example implementation.

FIG. 7 is a flowchart of a method for controlling a hydraulic system, inaccordance with an example implementation.

FIG. 8 is a flowchart of a method for operating a valve, in accordancewith an example implementation.

DETAILED DESCRIPTION

Pressure relief valves are configured to open at a preset pressure anddischarge fluid until pressure drops to acceptable levels in a system.In operation, the pressure relief valve can remain normally-closed untilpressure upstream reaches a desired setting pressure. The valve can then“crack” open when the setting pressure is reached, and continue to openfurther, allowing more flow as pressure increases. When upstreampressure falls below the setting pressure, the valve can close again.

In some examples, it may be desirable to have a pressure relief valvethat can be normally operating in a pressure relief mode to preventpressure levels in the system from exceeding the setting pressurecombined with the ability to block fluid flow from a source of fluid(e.g., a pump) and divert the fluid to another hydraulic component athigh pressure when actuated via an actuation signal (e.g., with anelectrical signal). For example, the valve may operate in aflow-blocking mode when actuated to provide or divert flow to ahydraulic motor at a high pressure level (e.g., 5000 pounds per squareinch (psi)) so as to accelerate the hydraulic motor or provide highinitial torque. Once the hydraulic motor reaches a desired speed, thevalve can be unactuated to provide a pressure relief setting that isless than such high pressure level. For instance, the pressure reliefsetting can be between 1000 and 3000 psi). This way, the valve allowsfluid to be provided to the hydraulic motor at a lower pressure level tomaintain its speed.

It may also be desirable to have such combined functionality in acompact package that does not involve using several valves, but rather asingle valve that combines multiple functionalities, thereby reducingmanufacturing cost. Further, having a compact package that performsmultiple functionalities reduces system size and weight.

Disclosed herein is a valve configured to normally operate in a pressurerelief mode where the valve operates as a relief valve and forms a pilotflow path configured to allow fluid flow therethrough when a reliefsetting (i.e., the setting pressure) is reached. Upon actuation, thevalve is configured to preclude the pilot flow path from forming andoperate in a flow-blocking mode to block fluid flow from the sourcethrough the valve. Un-actuating the valve enables the pilot flow path toform and renders the valve operating as a relief valve again.

FIG. 1 illustrates a cross-sectional side view of a valve 100 in apressure relief operation mode, in accordance with an exampleimplementation. The valve 100 may be inserted or screwed into a manifoldhaving ports corresponding to ports of the valve 100 described below,and can thus fluidly coupled the valve 100 to other components of ahydraulic system.

The valve 100 may include a main stage 102, a pilot stage 104, and asolenoid actuator 106. The valve 100 includes a housing 108 thatincludes a longitudinal cylindrical cavity therein. The longitudinalcylindrical cavity of the housing 108 is configured to house portions ofthe main stage 102, the pilot stage 104, and the solenoid actuator 106.

The main stage 102 includes a main sleeve 110 received at a distal endof the housing 108, and the main sleeve 110 is coaxial with the housing108. The valve 100 includes a first port 112 and a second port 114. Thefirst port 112 is defined at a nose or distal end of the main sleeve110. The second port 114 can include a first set of cross-holes that canbe referred to as main flow cross-holes, such as main flow cross-holes115A, 115B, disposed in a radial array about an exterior surface of themain sleeve 110. The second port 114 can also include a second set ofcross-holes that can be referred to as pilot flow cross-holes, such aspilot flow cross-hole 116 disposed in the housing 108.

The main sleeve 110 includes a respective longitudinal cylindricalcavity therein. The valve 100 includes a piston 118 that is disposed,and slidably accommodated, in the longitudinal cylindrical cavity of themain sleeve 110. The term “piston” is used herein to encompass any typeof movable element, such as a spool-type movable element or apoppet-type movable element. The piston 118 is shown in the figures as aspool-type movable element; however, it is contemplated that apoppet-type movable element can be used instead. In the case apoppet-type movable element is used, the inner peripheral surface of themain sleeve 110 can form a protrusion that operates as a seat for thepoppet-type movable element and reduce leakage through the valve 100.

Further, the term “slidably accommodated” is throughout herein toindicate that a first component (e.g., the piston 118) is positionedrelative to a second component (e.g., the main sleeve 110) withsufficient clearance therebetween, enabling movement of the firstcomponent relative to the second component in the proximal and distaldirections. As such, the first component (e.g., piston 118) is notstationary, locked, or fixedly disposed in the valve 100, but rather, isallowed to move relative to the second component (e.g., the main sleeve110).

The piston 118 has a cavity or main chamber 120 therein, and the valve100 includes a main spring 122 disposed in the main chamber 120 of thepiston 118. The valve 100 also includes a ring-shaped member 124disposed, at least partially, within the piston 118 at a distal endthereof. The ring-shaped member 124 includes a filter 126 and formstherein an orifice 128 that fluidly couples the first port 112 to themain chamber 120.

The valve 100 further includes a pilot seat member 130 fixedly disposedat the proximal end of in the main sleeve 110 within the cavity of thehousing 108. As shown in FIG. 1, the pilot seat member 130 has ashoulder formed by an exterior peripheral surface of the pilot seatmember 130. The shoulder interfaces with the proximal end of the mainsleeve 110 and interfaces with a shoulder 131 formed as a protrusionfrom an interior peripheral surface of the housing 108. As such, thepilot seat member 130 is fixedly disposed within the housing 108.

The main spring 122 is disposed in the main chamber 120 such that adistal end of the main spring 122 rests against the interior surface ofthe piston 118, and a proximal end of the main spring 122 rests againstthe pilot seat member 130. The pilot seat member 130 is fixed, and thusthe main spring 122 biases the piston 118 in the distal direction (tothe right in FIG. 1). The distal direction could also be referred to asa closing direction. The main spring 122 is configured as a weak spring(e.g., a spring with a spring rate of 8 pound-force/inch causing a 2pound-force biasing force on the piston 118). With such a low springrate, a low pressure level differential across the piston 118, e.g.,pressure level differential of 25 psi, can cause the piston 118 to movein the proximal direction against the biasing force of the main spring122.

Further, the pilot seat member 130 includes a plurality of channels. Forexample, the pilot seat member 130 can include a first longitudinalchannel 132 and a second longitudinal channel 133. The pilot seat member130 can also include a plurality of radial channels such as a firstradial channel 134 fluidly coupled to the first longitudinal channel 132and a second radial channel 135 fluidly coupled to the secondlongitudinal channel 133. The first radial channel 134 is axially spacedapart from the second radial channel 135 along a length of the pilotseat member 130.

The pilot seat member 130 forms a pilot seat 136 at a proximal end ofthe second longitudinal channel 133. The pilot stage 104 of the valve100 includes a pilot poppet 138 configured to be seated at the pilotseat 136. In particular, with the configuration shown in FIG. 1, thepilot poppet 138 forms a cavity at its distal end that is configured tohouse a pilot check ball 139. When the valve 100 is in the pressurerelief mode of operation depicted in FIG. 1, the pilot check ball 139 isconfigured to be seated at the pilot seat 136 until pressure level atthe first port 112 exceeds a pressure setting of the valve 100 asdescribed below.

The pilot poppet 138 and the pilot check ball 139 can be collectivelyreferred to as a pilot check member 140. The configuration of the pilotcheck member 140 that includes the pilot poppet 138 and the pilot checkball 139 as shown in FIG. 1 is an example for illustration. In otherexamples, a pilot check member can be configured as a poppet having anose section that tapers gradually, such that rather than using a checkball to block fluid flow, an exterior surface of the nose section of thepoppet is seated at the pilot seat 136 to block fluid flow.

As show in FIG. 1, the pilot seat member 130 has a pilot sleeve portion141 that extends in the proximal direction within the housing 108 andforms therein a pilot chamber 142 in which the pilot poppet 138 isdisposed and is slidably accommodated therein. The pilot poppet 138 isthus guided by an interior peripheral surface of the pilot sleeveportion 141 when the pilot poppet 138 moves axially in a longitudinaldirection.

The pilot stage 104 further includes a setting spring 144 disposed inthe pilot chamber 142, such that a distal end of the setting spring 144interfaces with the pilot poppet 138 and biases the pilot poppet 138toward the pilot seat 136. As such, the pilot poppet 138 operates as adistal spring cap for the setting spring 144.

A proximal end of the setting spring 144 rests against a washer 146disposed in the pilot chamber 142 and fixed in place via a springpreload adjustment screw 148. The spring preload adjustment screw 148has a threaded region on its exterior peripheral surface that threadedlyengages with a corresponding threaded region on an interior peripheralsurface of the pilot sleeve portion 141 of the pilot seat member 130.

The valve 100 can further include a pin 149 that secures that springpreload adjustment screw 148 within the pilot sleeve portion 141. Forexample, the pin 149 can be disposed partially within a longitudinalgroove formed in the exterior peripheral surface of the spring preloadadjustment screw 148 and partially within a longitudinal groove formedin the interior exterior peripheral surface of the pilot sleeve portion141. As such, the pin 149 couples and secures the spring preloadadjustment screw 148 to the pilot sleeve portion 141. In an example, thepin 149 can be pushed into the longitudinal groove formed on theexterior peripheral of the spring preload adjustment screw 148, and asthe pin 149 is forced in longitudinal groove, it deforms interiorthreads of the pilot sleeve portion 141. As such, once the springpreload adjustment screw 148 is screwed into the pilot seat member 130to a particular longitudinal or axial position, and the pin 149 isinserted, positions of the spring preload adjustment screw 148 and thewasher 146 are fixed, as the spring preload adjustment screw 148 can nolonger rotate relative to the pilot seat member 130.

The biasing force of the setting spring 144 determines the pressurerelief setting of the valve 100, where the pressure relief setting isthe pressure level of fluid at the first port 112 at which the valve 100can open to relieve fluid to the second port 114. Specifically, based ona spring rate of the setting spring 144 and the length of the settingspring 144, the setting spring 144 exerts a particular preload orbiasing force on the pilot poppet 138 in the distal direction, thuscausing the pilot check ball 139 to be seated at the pilot seat 136 ofthe pilot seat member 130. The pressure relief setting of the valve 100can be determined by dividing the biasing force that the setting spring144 applies to the pilot poppet 138 by an effective area of the pilotseat 136. The effective area of the pilot seat 136 can be estimated as acircular area having a diameter of the pilot seat 136. As an example forillustration, the pressure relief setting of the valve 100 can be about3000 psi.

As described below, when the valve 100 is unactuated as depicted in FIG.1 and when pressure level of fluid at the first port 112 causes thefluid to apply a fluid force on the pilot check ball 139, and thus onthe pilot poppet 138, in the proximal direction that overcomes thebiasing force of the setting spring 144 applied on the pilot poppet 138in the distal direction, the pilot poppet 138 and the pilot check ball139 move off the pilot seat 136. As the pilot check ball 139 isunseated, a pilot flow is allowed, thereby causing main flow from thefirst port 112 to the second port 114 and relieving the fluid asdescribed below. As a result, the hydraulic system that includes thevalve 100 is protected from pressure levels exceeding the settingpressure of the valve 100.

Adjusting longitudinal position of the spring preload adjustment screw148 within the pilot seat member 130 (prior to installation of the pin149) can adjust the biasing force of the setting spring 144. Forexample, if the spring preload adjustment screw 148 is rotated in afirst direction (e.g., in a clockwise direction), the spring preloadadjustment screw 148 may move axially in the distal direction (e.g., tothe right in FIG. 1) pushing the washer 146 in the distal direction,thus compressing the setting spring 144 and increasing the preload orbiasing force of the setting spring 144.

Conversely, rotating the spring preload adjustment screw 148 in a seconddirection (e.g., counter-clockwise) causes the spring preload adjustmentscrew 148 to move axially in the proximal direction, allowing thesetting spring 144 to push the washer 146 in the proximal direction. Thelength of the setting spring 144 thus increases and the preload orbiasing force of the setting spring 144 is reduced.

In examples, the spring preload adjustment screw 148 can be hollow suchthat a force sensor (e.g., a pin configured to have a force sensorcoupled thereto) can be inserted from the proximal end of the valve 100(prior to installation of the solenoid actuator 106) through the springpreload adjustment screw 148 to contact the washer 146 and measure thebiasing force of the setting spring 144. With this configuration, ifdesired, the biasing force of the setting spring 144, and thus thepressure relief setting of the valve 100, can be adjusted by adjustingthe longitudinal or axial position of the spring preload adjustmentscrew 148, prior to completing assembly of the valve 100 (i.e., prior toinstallation of the pin 149 and the solenoid actuator 106).

The solenoid actuator 106 includes a solenoid tube 150 configured as acylindrical housing or body disposed within and received at a proximalend of the housing 108, such that the solenoid tube 150 is coaxial withthe housing 108. For instance, the solenoid tube 150 can have a threadedregion disposed on an exterior peripheral surface at a distal endthereof that threadedly engages with a corresponding threaded regionformed on an interior peripheral surface of the housing 108 at aproximal end thereof. A solenoid coil 151 can be disposed about anexterior surface of the solenoid tube 150. The solenoid coil 151 isretained between a proximal end of the housing 108 and a coil nut 153having internal threads that can engage a threaded region formed on theexterior peripheral surface of the solenoid tube 150 at its proximalend.

The solenoid tube 150 forms therein a solenoid actuator chamberconfigured to house a plunger or armature 152. The armature 152 isslidably accommodated within the solenoid tube 150 (i.e., the armature152 can move axially within the solenoid tube 150).

The solenoid actuator 106 further includes a solenoid actuator sleeve154 received at the proximal end of the housing 108 and also disposedpartially within a distal end of the solenoid tube 150. The solenoidactuator sleeve 154 is slidably accommodated about the exteriorperipheral surface of the pilot sleeve portion 141 (i.e., the solenoidactuator sleeve 154 is positioned relative to the pilot sleeve portion141 with sufficient clearance therebetween, enabling movement of thesolenoid actuator sleeve 154 relative to the pilot sleeve portion 141 inthe proximal and distal directions, and thus the solenoid actuatorsleeve 154 is not stationary, locked, or fixedly disposed in the valve100, but rather, is allowed to move relative to the pilot sleeve portion141).

Further, the solenoid actuator sleeve 154 includes a set of cross-holes,such as cross-holes 155A, 155B, disposed in a radial array about anexterior surface of the solenoid actuator sleeve 154 and configured tocommunicate fluid therethrough. The solenoid actuator sleeve 154 alsoincludes an annular groove 157 disposed in an interior peripheralsurface of the solenoid actuator sleeve 154. The annular groove 157 isconfigured to selectively fluidly couple the first radial channel 134 tothe second radial channel 135 based on an axial position of the solenoidactuator sleeve 154.

In the state shown in FIG. 1, where the valve 100 operates in thepressure relief mode, the annular groove 157 partially overlaps thefirst radial channel 134 and partially overlaps the second radialchannel 135. With this configuration, the annular groove 157 forms anaxially extending flow passage that fluidly couples the first radialchannel 134 (which is fluidly coupled to the first longitudinal channel132) to the second radial channel 135 (which is fluidly coupled to thesecond longitudinal channel 133). In this manner, fluid received at thefirst port 112 can be communicated through the orifice 128, the mainchamber 120, the first longitudinal channel 132, the first radialchannel 134, the annular groove 157, the second radial channel 135, andthe second longitudinal channel 133 to the pilot check ball 139.

Further, the armature 152 is mechanically coupled to, or linked with,the solenoid actuator sleeve 154. As such, if the armature 152 movesaxially (e.g., in the proximal direction), the solenoid actuator sleeve154 moves along with the armature 152 in the same direction.

The armature 152 can be coupled to the solenoid actuator sleeve 154 inseveral ways. FIG. 2 illustrates a three-dimensional partial perspectiveview showing the armature 152 coupled to the solenoid actuator sleeve154, in accordance with an example implementation. As shown, thesolenoid actuator sleeve 154 can have a male T-shaped member 200, andthe armature 152 can have a corresponding female T-slot 202 configuredto receive the male T-shaped member 200 of the solenoid actuator sleeve154. With this configuration, the armature 152 and the solenoid actuatorsleeve 154 are coupled to each other, such that if the armature 152moves, the solenoid actuator sleeve 154 moves therewith.

Referring back to FIG. 1, the solenoid tube 150 further includes a polepiece 156 that can be separated from the armature 152 by an airgap 158.The pole piece 156 can be composed of material of high magneticpermeability.

The armature 152 includes therein a channel 160 and a chamber 162 formedwithin the armature 152 at a proximal end thereof. The chamber 162 isthus bounded by an interior surface of the pole piece 156 and aninterior surface of the armature 152. As such, fluid received at thefirst port 112 can be communicated through unsealed spaces within thevalve 100 to the channel 160, then to the chamber 162 and the airgap158. With this configuration, the armature 152 can be pressure-balancedwith fluid acting on both its proximal and distal ends.

Further, in examples, the chamber 162 can house a solenoid spring 164that biases the armature 152 toward the solenoid actuator sleeve 154 andthe pilot sleeve portion 141 such that there is no axial clearance oraxial “play” between the armature 152, the solenoid actuator sleeve 154,and the pilot sleeve portion 141, thus maintaining contact therebetween,when the valve 100 is unactuated. When the valve 100 is actuated, asdescribed below, the armature 152 can move in the proximal directionagainst the force of the solenoid spring 164, and thus the solenoidactuator sleeve 154 can move relative to (e.g., slide about the exteriorperipheral surface of) the pilot sleeve portion 141, which is fixed. Thesolenoid spring 164 can be a weak spring that applies a low force on thearmature 152. As an example for illustration, the solenoid spring 164can have a spring rate of 30 pound-force/inch causing a force of about2.5 pound-force on the armature 152).

As shown in FIG. 1, an exterior diameter of the solenoid actuator sleeve154 is smaller than an interior diameter of the housing 108, and thusannular space 166 is formed therebetween. Also, the pilot seat member130 includes a plurality of longitudinal channels or through-holes suchas longitudinal through-hole 168 disposed in a radial array around thepilot seat member 130. Further, the longitudinal through-hole 168 isfluidly coupled to the pilot flow cross-hole 116 of the housing 108 viaan annular undercut or annular groove 170 formed on the exteriorperipheral surface of the main sleeve 110 at a proximal end thereof.

Further, the pilot sleeve portion 141 includes cross-holes, such ascross-holes 172A, 172B disposed in a radial array about the pilot sleeveportion 141. The cross-holes 172A, 172B are fluidly coupled to anannular groove 174 formed in an exterior peripheral surface of the pilotsleeve portion 141.

The valve 100 is configured to operate in at least two modes ofoperation. The first mode of operation, when the valve 100 isunactuated, can be referred to as the pressure relief mode of operation.In this mode of operation, the valve 100 can allow pressure level offluid in the system (e.g., at the first port 112) to increase, but notexceed the pressure setting of the valve 100, which is determined by thesetting spring 144.

In the pressure relief mode of operation, as shown in FIG. 1, thesolenoid actuator sleeve 154 is in a first position, where the annulargroove 157 operates as an axially extending flow passage that fluidlycouples the first radial channel 134 (which is fluidly coupled to thefirst longitudinal channel 132) to the second radial channel 135 (whichis fluidly coupled to the second longitudinal channel 133). Further,when the solenoid actuator sleeve 154 is in the first position, thecross-holes 155A, 155B are aligned, or partially overlap, with theannular groove 174 of the pilot sleeve portion 141.

With this configuration and position of the solenoid actuator sleeve154, fluid at the first port 112 is communicated to the pilot check ball139 and the pilot poppet 138 through the orifice 128, the main chamber120, the first longitudinal channel 132, the first radial channel 134,the annular groove 157, the second radial channel 135, and the secondlongitudinal channel 133. When pressure level of the fluid at the firstport 112, which is communicated to the pilot check ball 139 and pilotpoppet 138, reaches or exceeds a predetermined setting pressuredetermined by the setting spring 144, fluid pushes the pilot check ball139 and the pilot poppet 138 in the proximal direction (to the left inFIG. 1) off the pilot seat 136. As mentioned above, the predeterminedsetting pressure is determined by dividing a preload force that thesetting spring 144 applies to the pilot poppet 138 by the effective areaof the pilot seat 136 (e.g., the circular area having the diameter ofthe pilot seat 136, which can be slightly larger than the diameter thesecond longitudinal channel 133). As an example for illustration, thepilot check ball 139 and the pilot poppet 138 can move a distance ofabout 0.05 inches off the pilot seat 136.

As a result of the pilot check ball 139 and the pilot poppet 138 beingunseated, a pilot flow path is formed and pilot fluid flow is generatedfrom the first port 112 to the second port 114. Particularly, fluid atthe first port 112 can flow through the orifice 128, the main chamber120, the first longitudinal channel 132, the first radial channel 134,the annular groove 157, the second radial channel 135, and the secondlongitudinal channel 133 to within the pilot sleeve portion 141 (e.g.,the pilot chamber 142) then through the cross-hole 172A, 172B, theannular groove 174, the cross-holes 155A, 155B, the annular space 166,the longitudinal through-hole 168, the annular groove 170, and the pilotflow cross-hole 116 to the second port 114. Such fluid flow from thefirst port 112 to the second port 114 through the pilot flow cross-hole116 can be referred to as the pilot flow. As an example forillustration, the pilot flow can amount to about 0.15 gallons per minute(GPM).

The pilot flow through the orifice 128, which operates as a flowrestriction, causes a pressure drop in the pressure level of the fluid.Thus, the pressure level of fluid in the main chamber 120 becomes lowerthan the pressure level of fluid received at the first port 112. As aresult, fluid at the first port 112 applies a force on the distal end ofthe piston 118 in the proximal direction (e.g., to the left in FIG. 1)that is larger than the force applied by fluid in the main chamber 120on the proximal end of the piston 118 in the distal direction (e.g., tothe right in FIG. 1).

Due to such force imbalance on the piston 118, a net force is applied tothe piston 118 in the proximal direction. When the net force overcomesthe biasing force of the main spring 122 on the piston 118, the netforce causes the piston 118 to move or be displaced axially in theproximal direction against the biasing force of the main spring 122. Asmentioned above, the main spring 122 has a low spring rate, and thus asmall pressure drop (e.g., when the pressure drop across the orifice 128is about 25 psi) can cause the net force to overcome the biasing forceof the main spring 122 on the piston 118.

Axial movement of the piston 118 in the proximal direction past edges ofthe main flow cross-holes 115A, 115B, causes the main flow cross-holes115A, 115B to be exposed, thereby forming a main flow path to allow mainflow directly from the first port 112 through the main flow cross-holes115A, 115B to the second port 114. Such direct flow from the first port112 to the second port 114 can be referred to as the main flow. As anexample for illustration, the main flow rate can amount to up to 25 GPMbased on the pressure setting of the valve 100 and the pressure dropbetween the first port 112 and the second port 114. The 25 GPM main flowrate is an example for illustration only. The valve 100 is scalable insize and different amounts of main flow rates can be achieved.

The second port 114 can be coupled to a low pressure reservoir or tankhaving fluid at low pressure level (e.g., atmospheric or low pressurelevel such as 10-70 psi). As such, pressurized fluid at the first port112 is relieved to the tank through the second port 114, therebyprecluding pressure level at the first port 112 from increasing furtherand protecting the hydraulic system from high pressure levels.

The valve 100 is further configured to operate in a second mode ofoperation when the valve 100 is actuated. The second mode of operationcan be referred to as the flow-blocking mode of operation.

FIG. 3 illustrates a cross-sectional side view of the valve 100 in aflow-blocking mode of operation, in accordance with an exampleimplementation. When an electric current is provided through thewindings of the solenoid coil 151, a magnetic field is generated. Thepole piece 156 directs the magnetic field through the airgap 158 towardthe armature 152, which is movable and is attracted toward the polepiece 156. In other words, when an electric current is applied to thesolenoid coil 151, the generated magnetic field forms a north and southpole in the pole piece 156 and the armature 152, and therefore the polepiece 156 and the armature 152 are attracted to each other. Because thepole piece 156 is fixed and the armature 152 is movable, the armature152 can traverse the airgap 158 toward the pole piece 156, and theairgap 158 is reduced in size as depicted in FIG. 3. As such, a solenoidforce is applied on the armature 152, where the solenoid force is apulling force that tends to pull the armature 152 in the proximaldirection against the force of the solenoid spring 164.

The solenoid force applied to the armature 152 is also applied to thesolenoid actuator sleeve 154, which is coupled to the armature 152 asdescribed with respect to FIG. 2. As the solenoid actuator sleeve 154moves in the proximal direction (to the left in FIG. 3) to a secondposition shown in FIG. 3, the annular groove 157 of the solenoidactuator sleeve 154 moves out of alignment, and no longer overlaps, withthe first radial channel 134 of the pilot seat member 130. As a result,the first radial channel 134 is blocked, and the annular groove 157 nolonger fluidly couples the first radial channel 134 to the second radialchannel 135. In other words, the second radial channel 135 is fluidlydecoupled from the first radial channel 134.

As such, in the flow-blocking mode of operation, when the valve 100 isactuated (i.e., when the solenoid coil 151 is energized), the pilot flowpath is blocked, as fluid at the first port 112 is not communicated fromthe first radial channel 134 to the second radial channel 135. In otherwords, actuating the valve 100 precludes the pilot flow path fromforming as fluid is not communicated to the second radial channel 135,and is thus not communicated to the pilot check ball 139.

Due to pilot flow path being blocked, no pilot flow is generated throughthe orifice 128, and no pressure drop occurs thereacross. The piston 118thus remains pressure-balanced based on fluid forces, and the mainspring 122 biases the piston 118 in the distal direction, therebyblocking the main flow cross-holes 115A, 115B, and blocking main flowfrom the first port 112 to the second port 114.

If the solenoid coil 151 is de-energized, the valve 100 reverts back tothe pressure relief mode of operation described above with respect toFIG. 1, where the annular groove 157 fluidly couples the first radialchannel 134 to the second radial channel 135, and the pilot flow pathcan form when the pressure level at the first port 112 exceeds thepressure setting of the valve 100. However, as long as the pressurelevel at the first port 112 is less than the pressure setting of thevalve 100, flow from the first port 112 to the second port 114 throughthe orifice 128, the main chamber 120, the first longitudinal channel132, the first radial channel 134, the annular groove 157, the secondradial channel 135, and the second longitudinal channel 133 is blockedat the pilot check ball 139. As a result, no pressure drop occurs acrossthe orifice 128, and the piston 118 is pressure-balanced due to thepressure level of fluid at the first port 112 and within the mainchamber 120 being substantially the same. The main spring 122 thusbiases the piston 118 in the distal direction to block the main flowcross-holes 115A, 115B and preclude fluid flow from the first port 112to the second port 114. In this manner, the valve 100 can allow pressurelevel at the first port 112 to increase. If the pressure level exceedsthe pressure setting of the valve 100, the pilot check ball 139 isunseated, and the pilot flow path is formed, thereby relieving the fluidat the first port 112 as described above with respect to FIG. 1.

The valve 100 can be referred to as a fixed setting pressure reliefvalve because once the preload of the setting spring 144 is set by thelocation of the spring preload adjustment screw 148 and the solenoidactuator 106 is installed, the preload of the setting spring 144 and itsbiasing force cannot be changed without disassembling the valve 100. Insome applications, it may be desirable to have a manual adjustmentactuator coupled to the valve so as to allow for manual modification ofthe preload of the setting spring 144, and thus modification of thepressure relief setting on the valve, while the valve is installed inthe hydraulic system without disassembling the valve.

FIG. 4 illustrates a cross-section side view of a valve 400 having amanual adjustment actuator 402, in accordance with an exampleimplementation. Identical components of both valves 100, 400 aredesignated with the same reference numbers. The valve 400 includes asolenoid tube 404 that differs from the solenoid tube 150 in that thesolenoid tube 404 has a two-chamber configuration that allows it toreceive the manual adjustment actuator 402.

FIG. 5 illustrates a cross-sectional side view of the solenoid tube 404,in accordance with an example implementation. As depicted, the solenoidtube 404 has a cylindrical body 500 having therein a first chamber 502within a distal side of the cylindrical body 500 and a second chamber504 within a proximal side of the cylindrical body 500. The solenoidtube 404 includes a pole piece 503 formed as a protrusion from aninterior peripheral surface of the cylindrical body 500. The pole piece503 separates the first chamber 502 from the second chamber 504. Inother words, the pole piece 503 divides a hollow interior of thecylindrical body 500 into the first chamber 502 and the second chamber504. The pole piece 503 can be composed of material of high magneticpermeability.

Further, the pole piece 503 defines a channel 505 therethrough. In otherwords, an interior peripheral surface of the solenoid tube 404 at orthrough the pole piece 503 forms the channel 505, which fluidly couplesthe first chamber 502 to the second chamber 504. As such, pressurizedfluid provided to the first chamber 502 is communicated through thechannel 505 to the second chamber 504.

In examples, the channel 505 can be configured to receive a pintherethrough so as to transfer linear motion of one component in thesecond chamber 504 to another component in the first chamber 502 andvice versa. As such, the channel 505 can include chamferedcircumferential surfaces at its ends (e.g., an end leading into thefirst chamber 502 and another end leading into the second chamber 504)to facilitate insertion of such a pin therethrough.

The solenoid tube 404 has a distal end 506 configured to be coupled tothe housing 108 and a proximal end 508 configured to be coupled to andreceive the manual adjustment actuator 402. Particularly, the solenoidtube 404 can have a first threaded region 510 disposed on an exteriorperipheral surface of the cylindrical body 500 at the distal end 506that is configured to threadedly engage with corresponding threadsformed in the interior peripheral surface of the housing 108.

Also, the solenoid tube 404 can have a second threaded region 512disposed on the exterior peripheral surface of the cylindrical body 500at the proximal end 508 and configured to be threadedly engage withcorresponding threads formed in the interior peripheral surface of thecoil nut 153. Further, the solenoid tube 404 can have a third threadedregion 514 disposed on an interior peripheral surface of the cylindricalbody 500 at the proximal end 508 and configured to threadedly engagewith corresponding threads formed in a component of the manualadjustment actuator 402 as described below. The solenoid tube 404 canalso have one or more shoulders formed in the interior peripheralsurface of the cylindrical body 500 that can mate with respectiveshoulders of the manual adjustment actuator 402 to enable alignment ofthe manual adjustment actuator 402 within the solenoid tube 404.

Referring back to FIG. 4, the solenoid tube 404 is configured to housean armature 406 in the first chamber 502. The armature 406 has alongitudinal channel 408 formed therein. The armature 406 also includesan annular internal groove or T-slot 410 configured to receive the maleT-shaped member 200 of the solenoid actuator sleeve 154. The armature406 further includes a protrusion 412 from its interior peripheralsurface. The solenoid spring 164 is configured to rest on the protrusion412 to bias the armature 406 in the distal direction.

As mentioned above, the solenoid tube 404 includes the pole piece 503formed as a protrusion from the interior peripheral surface of thesolenoid tube 404. The pole piece 503 is separated from the armature 406by the airgap 158.

The manual adjustment actuator 402 is configured to allow for adjustingthe pressure relief setting of the valve 400 without disassembling thevalve 400. The manual adjustment actuator 402 includes a pin 414disposed through the channel 505. The pin 414 is coupled to a spring cap416 that interfaces with the setting spring 144 of the valve 400. Assuch, the valve 400 differs from the valve 100 in that, rather than thesetting spring 144 interfacing with the spring preload adjustment screw148, which is fixed once screwed to a particular position, the valve 400includes the spring cap 416, which is movable via the pin 414 and canadjust the length of the setting spring 144.

The manual adjustment actuator 402 includes an adjustment piston 418that interfaces with or contacts the pin 414, such that axial motion ofthe adjustment piston 418 causes the pin 414 and the spring cap 416coupled thereto to move axially therewith. The adjustment piston 418 canbe threadedly coupled to a nut 420 at threaded region 422. The nut 420in turn is threadedly coupled to the solenoid tube 404 at the threadedregion 514. As such, the adjustment piston 418 is coupled to thesolenoid tube 404 via the nut 420. Further, the adjustment piston 418 isthreadedly coupled at threaded region 424 to another nut 426.

The adjustment piston 418 is axially movable within the second chamber504 of the solenoid tube 404. For instance, the adjustment piston 418can include an adjustment screw 428, such that if the adjustment screw428 is rotated in a first rotational direction (e.g., clockwise) theadjustment piston 418 moves in the distal direction (e.g., to the rightin FIG. 4) by engaging more threads of the threaded regions 422, 424. Ifthe adjustment screw 428 is rotated in a second rotational direction(e.g., counter-clockwise) the adjustment piston 418 is allowed to movein the proximal direction (e.g., to the left in FIG. 4) by disengagingsome threads of the threaded regions 422, 424.

While the distal end of the setting spring 144 is coupled to or restsagainst the pilot poppet 138, the proximal end of the setting spring 144rests against the spring cap 416, which is coupled to the adjustmentpiston 418 via the pin 414. As such, axial motion of the adjustmentpiston 418 results in a change in the length of the setting spring 144.As a result, the biasing force that the setting spring 144 exerts on thepilot poppet 138, and thus the pressure relief setting of the valve 400,is changed. With this configuration, the pressure relief setting of thevalve 400 can be adjusted via the manual adjustment actuator 402 withoutdisassembling the valve 400. As an example for illustration, theadjustment piston 418 can have a stroke of about 0.15 inches, whichcorresponds to a pressure relief setting range between 0 psi and 5000psi.

The valve 400 is depicted in FIG. 4 in the pressure relief operationmode (similar to the valve 100 in FIG. 1). Similar to the valve 100, thevalve 400 can be switched to the flow-blocking operation mode byenergizing the solenoid coil 151 so as to move the armature 406 and thesolenoid actuator sleeve 154 in the proximal direction (e.g., to theleft in FIG. 4).

As described above, as a result of the solenoid actuator sleeve 154moving in the proximal direction, the annular groove 157 of the solenoidactuator sleeve 154 moves out of alignment, and no longer overlaps, withthe first radial channel 134 of the pilot seat member 130, and thus nolonger fluidly couples the first radial channel 134 to the second radialchannel 135, and fluid is not communicated to second longitudinalchannel 133 and the pilot check ball 139. The valve 400 thus switches tothe flow-blocking mode of operation, precluding the pilot flow path fromforming, and blocking fluid at the first port 112.

The configurations and components shown in FIGS. 1-5 are examples forillustration, and different configurations and components could be used.For example, components can be integrated into a single component or acomponent can be divided into multiple components. As another example,different types of springs could be used, and other components could bereplaced by components that perform a similar functionality. Further,although the solenoid actuator 106 is shown and described as a pull-typesolenoid actuator, in other example implementations the valve 100, 400can be configured such that a push-type solenoid actuator can be used,where the armature 152, 406 can be pushed in the distal direction whenthe solenoid coil 151 is energized.

The valves 100, 400 can be referred to as pressure relief valves thatare switchable to operating as flow-blocking valves. Particularly, thevalve 100 or 400 can be included in hydraulic systems so as to operatein a pressure relief mode to build pressure in the hydraulic system andprotect the hydraulic system against undesirable increases in pressurelevel when the valve is unactuated, and switch to a flow-blocking modeto block fluid at the first port 112 and preclude fluid flow through thevalve 100, 400 when the valve is actuated.

FIG. 6 illustrates a hydraulic system 600 using the valve 400, inaccordance with an example implementation. The valve 400 is depictedsymbolically in FIG. 6.

The hydraulic system 600 includes a source 602 of fluid. The source 602of fluid can, for example, be a pump configured to provide fluid to thefirst port 112 of the valve 400. Such pump can be a fixed displacementpump, a variable displacement pump, or a load-sensing variabledisplacement pump, as examples. Additionally or alternatively, thesource 602 of fluid can be an accumulator or another component (e.g., avalve) of the hydraulic system 600, such that the source 602 is fluidlycoupled to the first port 112 of the valve 400.

As described above, when the valve 400 is unactuated, the valve 400operates in a pressure relief mode. In the pressure relief mode,pressure level of fluid provided by the source 602 is allowed to buildup or increase without exceeding a particular pressure level, thusproviding pressurized fluid to other portions, components, equipment, oractuators of the hydraulic system 600. Such other portions, components,equipment, or actuators are represented in FIG. 6 by block 603. Forinstance, the block 603 can represent a hydraulic motor along with othercomponents. When the valve 400 operates in the pressure relief mode,fluid from the source 602 is diverted to the hydraulic motor at apressure level that does not exceed the pressure setting of the valve400 so as to, for example, maintain a particular speed of the hydraulicmotor.

If the pressure level of fluid supplied by the source 602 exceeds thepressure setting of the valve 400, such that pressurized fluid at thefirst port 112 applies a fluid force on the pilot check ball 139 thatovercomes the biasing force of the setting spring 144, pressurized fluidunseats the pilot check ball 139 and the pilot flow path is opened.Opening the pilot flow path allows pilot flow, symbolized by arrow 604in FIG. 6, from the first port 112 to the second port 114 through theorifice 128, the main chamber 120, the first longitudinal channel 132,the first radial channel 134, the annular groove 157, the second radialchannel 135, and the second longitudinal channel 133 to within the pilotsleeve portion 141, then through the cross-hole 172A, 172B, the annulargroove 174, the cross-holes 155A, 155B, the annular space 166, thelongitudinal through-hole 168, the annular groove 170, and the pilotflow cross-hole 116. The pilot flow allows the piston 118 to move,thereby allowing main flow from the first port 112 to the second port114 via the main flow cross-holes 115A, 115B and relieving fluid at thefirst port 112 to the second port 114, which can be coupled to a tank606. The pressure relief mode is represented by symbol 608 in FIG. 6.This way, the speed of the hydraulic motor might not increase beyond aparticular speed.

As depicted symbolically in FIG. 6 by arrow 610, the biasing force ofthe setting spring 144 can be adjusted (e.g., via the manual adjustmentactuator 402 as described above). The valve 100 can be used in thehydraulic system 600 instead of the valve 400; however, the valve 100can be depicted without the arrow 610.

The hydraulic system 600 can further include a controller 612. Thecontroller 612 can include one or more processors or microprocessors andmay include data storage (e.g., memory, transitory computer-readablemedium, non-transitory computer-readable medium, etc.). The data storagemay have stored thereon instructions that, when executed by the one ormore processors of the controller 612, cause the controller 612 toperform operations described herein. Signal lines to and from thecontroller 612 are depicted as dashed lines in FIG. 6. The controller612 can receive input or input information comprising sensor informationvia signals from various sensors or input devices in the hydraulicsystem 600, and in response provide electric signals to variouscomponents of the hydraulic system 600.

The controller 612 can receive a command or input information to switchthe valve 400 from operating in a pressure relief mode to aflow-blocking operation mode. For example, the controller 612 mayreceive an input or sensor information indicating a request to operatethe valve 400 in a flow-blocking mode to provide or divert flow at ahigh pressure level (e.g., 5000 psi) to the hydraulic motor.

In response to the command or input information requesting or indicatingthe mode switch, the controller 612 can send a command signal to thesolenoid coil 151 of the solenoid actuator 106 of the valve 400 togenerate a solenoid force on the armature 406. When the solenoid forceovercomes the biasing force of the solenoid spring 164, the armature 406and the solenoid actuator sleeve 154 move in the proximal direction asdescribed above. As a result, the annular groove 157 no longer overlapswith the first radial channel 134, and the pilot flow path might notform. As such, fluid at the first port 112 is blocked by the valve 400.Blocking fluid at the first port 112 and precluding it from flowing tothe second port 114 is symbolized by blocked fluid path symbol 614 inFIG. 6.

When the valve 400 operates in the flow-blocking mode, fluid from thesource 602 is blocked at the first port 112 of the valve 400 anddiverted to the block 603, e.g., the hydraulic motor, at the highpressure level so as to accelerate the hydraulic motor or provide hightorque. The hydraulic system 600 can include another relief valve (e.g.,within the block 603) that can preclude the pressure level fromincreasing beyond a maximum pressure level to protect the hydraulicsystem 600.

FIG. 7 is a flowchart of a method 700 for controlling a hydraulicsystem, in accordance with an example implementation. The method 700can, for example, be performed by a controller such as the controller612 to control the hydraulic system 600.

The method 700 may include one or more operations, or actions asillustrated by one or more of blocks 702-704. Although the blocks areillustrated in a sequential order, these blocks may in some instances beperformed in parallel, and/or in a different order than those describedherein. Also, the various blocks may be combined into fewer blocks,divided into additional blocks, and/or removed based upon the desiredimplementation.

In addition, for the method 700 and other processes and operationsdisclosed herein, the flowchart shows operation of one possibleimplementation of present examples. In this regard, each block mayrepresent a module, a segment, or a portion of program code, whichincludes one or more instructions executable by a processor or acontroller for implementing specific logical operations or steps in theprocess. The program code may be stored on any type of computer readablemedium or memory, for example, such as a storage device including a diskor hard drive. The computer readable medium may include a non-transitorycomputer readable medium or memory, for example, such ascomputer-readable media that stores data for short periods of time likeregister memory, processor cache and Random Access Memory (RAM). Thecomputer readable medium may also include non-transitory media ormemory, such as secondary or persistent long term storage, like readonly memory (ROM), optical or magnetic disks, compact-disc read onlymemory (CD-ROM), for example. The computer readable media may also beany other volatile or non-volatile storage systems. The computerreadable medium may be considered a computer readable storage medium, atangible storage device, or other article of manufacture, for example.In addition, for the method 700 and other processes and operationsdisclosed herein, one or more blocks in FIG. 7 may represent circuitryor digital logic that is arranged to perform the specific logicaloperations in the process.

At block 702, the method 700 includes receiving input informationindicating a request to switch the valve 100, 400 from operating in apressure relief mode to a flow-blocking operation mode. The valve 100,400 is normally operating in the pressure relief mode as described abovewith respect to FIGS. 1 and 4 when the valve 100, 400 is unactuated.

At block 704, the method 700 includes, based on the input information,sending a signal to the solenoid coil 151 to switch the valve 100, 400to operate in the flow-blocking operation mode. As described above, thecontroller 612 can provide a signal to the solenoid coil 151 to causethe armature 152, 406 to apply a force on the solenoid actuator sleeve154 in the proximal direction, such that as the solenoid actuator sleeve154 moves, the valve 100, 400 is switched to operating in theflow-blocking mode as described above.

FIG. 8 is a flowchart of a method 800 for operating a valve, inaccordance with an example implementation. The method 800 shown in FIG.8 presents an example of a method that could be used with the valves100, 400, shown throughout the Figures, for example. The method 800 mayinclude one or more operations, functions, or actions as illustrated byone or more of blocks 802-808. Although the blocks are illustrated in asequential order, these blocks may also be performed in parallel, and/orin a different order than those described herein. Also, the variousblocks may be combined into fewer blocks, divided into additionalblocks, and/or removed based upon the desired implementation. It shouldbe understood that for this and other processes and methods disclosedherein, flowcharts show functionality and operation of one possibleimplementation of present examples. Alternative implementations areincluded within the scope of the examples of the present disclosure inwhich functions may be executed out of order from that shown ordiscussed, including substantially concurrent or in reverse order,depending on the functionality involved, as would be understood by thosereasonably skilled in the art.

At block 802, the method 800 includes operating the valve 100, 400 in apressure relief mode, wherein when pressure level of pressurized fluidreceived at the first port 112 of the valve 100, 400 exceeds aparticular pressure level (i.e., the pressure relief setting), thepressurized fluid overcomes a biasing force of the setting spring 144 ofthe valve 100, 400, thereby causing the pilot check member 140 to beunseated off the pilot seat member 130 and opening the pilot flow pathvia: (i) the first radial channel 134 and the second radial channel 135formed in the pilot seat member 130 and fluidly coupled to each other bythe annular groove 157 disposed in the interior peripheral surface ofthe solenoid actuator sleeve 154, and (ii) the cross-holes 172A, 172B ofthe pilot sleeve portion 141 of the pilot seat member 130, which arealigned with the cross-holes 155A, 155B of the solenoid actuator sleeve154, to allow pilot flow from the first port 112 to the second port 114.

At block 804, the method 800 includes, in response to pilot flow throughthe pilot flow path, causing the piston 118 to move (i.e., in theproximal direction), thereby allowing main flow from the first port 112to the second port 114.

At block 806, the method 800 includes receiving an electric signal(e.g., from the controller 612) energizing the solenoid coil 151 of asolenoid actuator (e.g., the solenoid actuator 106) of the valve 100,400 to switch the valve 100, 400 to a flow-blocking mode of operation.The controller 612 can receive a request to switch the valve 100, 400 toa flow-blocking mode to block fluid at the first port 112. In response,the controller 612 sends the electric signal to the solenoid coil 151 toenergize it.

At block 808, the method 800 includes, responsively, causing thearmature 152, 406 and the solenoid actuator sleeve 154 coupled to thearmature 152, 406 to move, thereby moving the annular groove 157 out ofalignment with the first radial channel 134, causing the first radialchannel 134 to be blocked, precluding the pilot flow path from forming,and blocking fluid at the first port 112.

The detailed description above describes various features and operationsof the disclosed systems with reference to the accompanying figures. Theillustrative implementations described herein are not meant to belimiting. Certain aspects of the disclosed systems can be arranged andcombined in a wide variety of different configurations, all of which arecontemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall implementations, with the understanding that not allillustrated features are necessary for each implementation.

Additionally, any enumeration of elements, blocks, or steps in thisspecification or the claims is for purposes of clarity. Thus, suchenumeration should not be interpreted to require or imply that theseelements, blocks, or steps adhere to a particular arrangement or arecarried out in a particular order.

Further, devices or systems may be used or configured to performfunctions presented in the figures. In some instances, components of thedevices and/or systems may be configured to perform the functions suchthat the components are actually configured and structured (withhardware and/or software) to enable such performance. In other examples,components of the devices and/or systems may be arranged to be adaptedto, capable of, or suited for performing the functions, such as whenoperated in a specific manner.

By the term “substantially” or “about” it is meant that the recitedcharacteristic, parameter, or value need not be achieved exactly, butthat deviations or variations, including for example, tolerances,measurement error, measurement accuracy limitations and other factorsknown to skill in the art, may occur in amounts that do not preclude theeffect the characteristic was intended to provide

The arrangements described herein are for purposes of example only. Assuch, those skilled in the art will appreciate that other arrangementsand other elements (e.g., machines, interfaces, operations, orders, andgroupings of operations, etc.) can be used instead, and some elementsmay be omitted altogether according to the desired results. Further,many of the elements that are described are functional entities that maybe implemented as discrete or distributed components or in conjunctionwith other components, in any suitable combination and location.

While various aspects and implementations have been disclosed herein,other aspects and implementations will be apparent to those skilled inthe art. The various aspects and implementations disclosed herein arefor purposes of illustration and are not intended to be limiting, withthe true scope being indicated by the following claims, along with thefull scope of equivalents to which such claims are entitled. Also, theterminology used herein is for the purpose of describing particularimplementations only, and is not intended to be limiting.

What is claimed is:
 1. A valve comprising: a pilot seat membercomprising: (i) a first channel and a second channel, wherein the firstchannel is fluidly coupled to a first port of the valve, (ii) a pilotseat, and (iii) a pilot sleeve portion comprising a pilot chamber and across-hole disposed in an exterior peripheral surface of the pilotsleeve portion; a pilot check member disposed in the pilot chamber andsubjected to a biasing force of a setting spring disposed in the pilotchamber, wherein the biasing force acts in a distal direction to seatthe pilot check member at the pilot seat, wherein the pilot check memberis configured to be subjected to a fluid force of fluid in the secondchannel of the pilot seat member acting on the pilot check member in aproximal direction; and a solenoid actuator sleeve slidably accommodatedabout the exterior peripheral surface of the pilot sleeve portion of thepilot seat member, wherein the solenoid actuator sleeve comprises across-hole disposed in an exterior peripheral surface of the solenoidactuator sleeve and an annular groove disposed in an interior peripheralsurface of the solenoid actuator sleeve, wherein the cross-hole of thesolenoid actuator sleeve is fluidly coupled to a second port of thevalve, and wherein: when the valve is unactuated: (i) the cross-hole ofthe solenoid actuator sleeve is aligned with the cross-hole of the pilotsleeve portion, and (ii) the annular groove fluidly couples the secondchannel to the first channel to enable generation of pilot flow from thefirst port to the second port when the fluid force overcomes the biasingforce and the pilot check member is unseated, and when the valve isactuated, the solenoid actuator sleeve and the annular groove moveaxially, thereby causing the second channel to be fluidly decoupled fromthe first channel and precluding pilot flow from the first port to thesecond port.
 2. The valve of claim 1, wherein when the valve isunactuated: (i) the annular groove forms an axially extending flowpassage that overlaps, at least partially, the first channel and thesecond channel of the pilot seat member to fluidly couple the secondchannel to the first channel, and when the valve is actuated, theannular groove moves out of alignment with the first channel, therebycausing the second channel to be fluidly decoupled from the firstchannel and precluding pilot flow from the first port to the secondport.
 3. The valve of claim 1, wherein: when the valve is unactuated andwhen the fluid force overcomes the biasing force of the setting springon the pilot check member, the pilot check member is unseated and apilot flow path is formed to allow pilot flow from the first port to thesecond port through the first channel, the annular groove, the secondchannel, the cross-hole of the pilot sleeve portion, and the cross-holeof the solenoid actuator sleeve, thereby causing a piston to moveaxially and open a main flow path from the first port to the second portto relieve fluid from the first port to the second port, and when thevalve is actuated, the annular groove of the solenoid actuator sleevemoves out of alignment with the first channel, thereby blocking thefirst channel and precluding the pilot flow path from forming.
 4. Thevalve of claim 1, further comprising: a housing having a longitudinalcylindrical cavity therein and having a cross-hole disposed in anexterior peripheral surface of the housing; and a main sleeve disposed,at least partially, in the longitudinal cylindrical cavity of thehousing, wherein the main sleeve includes the first port at a distal endof the main sleeve and includes one or more cross-holes disposed on anexterior peripheral surface of the main sleeve, wherein the cross-holeof the housing and the one or more cross-holes of the main sleeve formthe second port.
 5. The valve of claim 4, further comprising: a pistondisposed within the main sleeve and configured to be axially movabletherein, wherein the piston comprises a main chamber therein, andwherein the main chamber is fluidly coupled to the first port and thefirst channel of the pilot seat member.
 6. The valve of claim 5, whereinthe first channel is a first radial channel and the second channel is asecond radial channel axially spaced apart from the first radialchannel, and wherein the pilot seat member further comprises: (i) afirst longitudinal channel fluidly coupled to the main chamber and thefirst radial channel, and (ii) a second longitudinal channel fluidlycoupled to the second radial channel, wherein the pilot seat is formedat a proximal end of the second longitudinal channel.
 7. The valve ofclaim 6, wherein when the valve is unactuated and when the fluid forceovercomes the biasing force of the setting spring on the pilot checkmember, the pilot check member is unseated and a pilot flow path isformed to allow pilot flow from the first port to the second port,wherein the pilot flow path comprises: the first longitudinal channel,the first radial channel, the annular groove, the second radial channel,the second longitudinal channel, the cross-hole of the pilot sleeveportion, and the cross-hole of the solenoid actuator sleeve.
 8. Thevalve of claim 7, wherein the pilot flow path further comprises (i) anannular space formed between an exterior peripheral surface of thesolenoid actuator sleeve and an interior peripheral surface of thehousing, (ii) a longitudinal through-hole formed in the pilot seatmember, and (iii) the cross-hole of the housing.
 9. The valve of claim1, further comprising: a solenoid actuator comprising a solenoid coil, apole piece, and an armature that is mechanically coupled to the solenoidactuator sleeve, such that when the solenoid coil is energized, thearmature and the solenoid actuator sleeve coupled thereto are pulledaxially toward the pole piece, thereby moving the annular groove out ofalignment with the first channel to fluidly decouple the second channelfrom the first channel and block the first channel.
 10. The valve ofclaim 9, wherein the armature comprises a T-slot formed as an annularinternal groove, wherein the solenoid actuator sleeve comprises a maleT-shaped member, and wherein the T-slot of the armature is configured toreceive the male T-shaped member of the solenoid actuator sleeve tomechanically couple the armature to the solenoid actuator sleeve. 11.The valve of claim 9, wherein the solenoid actuator further comprises asolenoid tube, and wherein the solenoid tube comprises: (i) acylindrical body, (ii) a first chamber defined within the cylindricalbody and configured to receive the armature of the solenoid actuatortherein, and (iii) a second chamber defined within the cylindrical body,wherein the pole piece is formed as a protrusion from an interiorperipheral surface of the cylindrical body, wherein the pole piece isdisposed between the first chamber and the second chamber, and whereinthe pole piece defines a channel therethrough, such that the channelfluidly couples the first chamber to the second chamber.
 12. The valveof claim 11, further comprising: a manual adjustment actuator having:(i) an adjustment piston disposed, at least partially, in the secondchamber of the solenoid tube, (ii) a pin disposed through the channel ofthe pole piece and through the armature, wherein a proximal end of thepin contacts the adjustment piston and a distal end of the pin iscoupled to a spring cap against which a proximal end of the settingspring rests, such that axial motion of the adjustment piston causes thepin and the spring cap coupled thereto to move axially, therebyadjusting the biasing force of the setting spring.
 13. A hydraulicsystem comprising: a source of fluid; a reservoir; and a valve having afirst port fluidly coupled to the source of fluid, and a second portfluidly coupled to the reservoir, wherein the valve comprises: a pilotseat member comprising: (i) a first channel and a second channel,wherein the first channel is fluidly coupled to the first port of thevalve, (ii) a pilot seat, and (iii) a pilot sleeve portion comprising apilot chamber and a cross-hole disposed in an exterior peripheralsurface of the pilot sleeve portion, a pilot check member disposed inthe pilot chamber and subjected to a biasing force of a setting springdisposed in the pilot chamber, wherein the biasing force acts in adistal direction to seat the pilot check member at the pilot seat,wherein the pilot check member is configured to be subjected to fluidforce of fluid in the second channel of the pilot seat member acting onthe pilot check member in a proximal direction, and a solenoid actuatorsleeve slidably accommodated about the exterior peripheral surface ofthe pilot sleeve portion of the pilot seat member, wherein the solenoidactuator sleeve comprises a cross-hole disposed in an exteriorperipheral surface of the solenoid actuator sleeve and an annular groovedisposed in an interior peripheral surface of the solenoid actuatorsleeve, wherein the cross-hole of the solenoid actuator sleeve isfluidly coupled to the second port of the valve, and wherein: when thevalve is unactuated: (i) the cross-hole of the solenoid actuator sleeveis aligned with the cross-hole of the pilot sleeve portion, and (ii) theannular groove fluidly couples the second channel to the first channelto enable generation of pilot flow from the first port to the secondport when the fluid force overcomes the biasing force and the pilotcheck member is unseated, and when the valve is actuated, the solenoidactuator sleeve and the annular groove move axially, thereby causing thesecond channel to be fluidly decoupled from the first channel andprecluding pilot flow from the first port to the second port.
 14. Thehydraulic system of claim 13, wherein the first channel is a firstradial channel and the second channel is a second radial channel axiallyspaced apart from the first radial channel, wherein when the valve isunactuated: (i) the annular groove forms an axially extending flowpassage that overlaps, at least partially, the first radial channel andthe second radial channel of the pilot seat member to fluidly couple thesecond radial channel to the first radial channel, such that when thefluid force overcomes the biasing force of the setting spring on thepilot check member, the pilot check member is unseated and a pilot flowpath is formed to allow pilot flow from the first port to the secondport through the first radial channel, the annular groove, the secondradial channel, the cross-hole of the pilot sleeve portion, and thecross-hole the solenoid actuator sleeve, thereby causing a piston tomove axially and open a main flow path from the first port to the secondport to relieve fluid from the first port to the second port, and whenthe valve is actuated, the annular groove moves out of alignment withthe first radial channel, thereby causing the second radial channel tobe fluidly decoupled from the first radial channel, blocking the firstradial channel, and precluding pilot flow from the first port to thesecond port.
 15. The hydraulic system of claim 13, wherein the valvefurther comprises: a housing having a longitudinal cylindrical cavitytherein and having a cross-hole disposed in an exterior peripheralsurface of the housing; a main sleeve disposed, at least partially, inthe longitudinal cylindrical cavity of the housing, wherein the mainsleeve includes the first port at a distal end of the main sleeve andincludes one or more cross-holes disposed on an exterior peripheralsurface of the main sleeve, wherein the cross-hole of the housing andthe one or more cross-holes of the main sleeve form the second port; anda piston disposed within the main sleeve and configured to be axiallymovable therein, wherein the piston comprises a main chamber therein,and wherein the main chamber is fluidly coupled to the first port andthe first channel of the pilot seat member.
 16. The hydraulic system ofclaim 15, wherein the first channel is a first radial channel and thesecond channel is a second radial channel axially spaced apart from thefirst radial channel, and wherein the pilot seat member furthercomprises: (i) a first longitudinal channel fluidly coupled to the mainchamber and the first radial channel, and (ii) a second longitudinalchannel fluidly coupled to the second radial channel, wherein the pilotseat is formed at a proximal end of the second longitudinal channel,wherein: when the valve is unactuated and when the fluid force overcomesthe biasing force of the setting spring on the pilot check member, thepilot check member is unseated and a pilot flow path is formed to allowpilot flow from the first port to the second port, wherein the pilotflow path comprises: the first longitudinal channel, the first radialchannel, the annular groove, the second radial channel, the secondlongitudinal channel, the cross-hole of the pilot sleeve portion, andthe cross-hole of the solenoid actuator sleeve.
 17. The hydraulic systemof claim 13, further comprising: a solenoid actuator comprising (i) asolenoid coil, (ii) a pole piece, (iii) an armature that is mechanicallycoupled to the solenoid actuator sleeve such that when the solenoid coilis energized, the armature and the solenoid actuator sleeve coupledthereto are pulled axially toward the pole piece, thereby moving theannular groove out of alignment with the first channel, and (iv) asolenoid tube, wherein the solenoid tube comprises: (i) a cylindricalbody, (ii) a first chamber defined within the cylindrical body andconfigured to receive the armature of the solenoid actuator therein, and(iii) a second chamber defined within the cylindrical body, wherein thepole piece is formed as a protrusion from an interior peripheral surfaceof the cylindrical body, wherein the pole piece is disposed between thefirst chamber and the second chamber, and wherein the pole piece definesa channel therethrough, such that the channel fluidly couples the firstchamber to the second chamber; and a manual adjustment actuator having:(i) an adjustment piston disposed, at least partially, in the secondchamber of the solenoid tube, (ii) a pin disposed through the channel ofthe pole piece and through the armature, wherein a proximal end of thepin contacts the adjustment piston and a distal end of the pin iscoupled to a spring cap against which a proximal end of the settingspring rests, such that axial motion of the adjustment piston causes thepin and the spring cap coupled thereto to move axially, therebyadjusting the biasing force of the setting spring.
 18. A valvecomprising: a housing having a longitudinal cylindrical cavity thereinand having a cross-hole disposed in an exterior peripheral surface ofthe housing; a main sleeve disposed, at least partially, in thelongitudinal cylindrical cavity of the housing, wherein the main sleeveincludes a first port at a distal end of the main sleeve and includesone or more cross-holes disposed on an exterior peripheral surface ofthe main sleeve, wherein the cross-hole of the housing and the one ormore cross-holes of the main sleeve form a second port; a pistondisposed within the main sleeve and configured to be axially movabletherein, wherein the piston comprises a main chamber therein, andwherein the main chamber is fluidly coupled to the first port via anorifice; a pilot seat member comprising: (i) a first channel and asecond channel, wherein the first channel is fluidly coupled to thefirst port, (ii) a pilot seat, and (iii) a pilot sleeve portioncomprising a pilot chamber and a cross-hole disposed in an exteriorperipheral surface of the pilot sleeve portion; a pilot check memberdisposed in the pilot chamber and subjected to a biasing force of asetting spring disposed in the pilot chamber, wherein the biasing forceacts in a distal direction to seat the pilot check member at the pilotseat, wherein the pilot check member is configured to be subjected tofluid force of fluid in the second channel of the pilot seat memberacting on the pilot check member in a proximal direction; and a solenoidactuator sleeve slidably accommodated about the exterior peripheralsurface of the pilot sleeve portion of the pilot seat member, whereinthe solenoid actuator sleeve comprises a cross-hole disposed in anexterior peripheral surface of the solenoid actuator sleeve and anannular groove disposed in an interior peripheral surface of thesolenoid actuator sleeve, wherein the cross-hole of the solenoidactuator sleeve is fluidly coupled to the second port of the valve, andwherein the annular groove is configured to selectively fluidly couplethe first channel to the second channel based on a position of thesolenoid actuator sleeve.
 19. The valve of claim 18, wherein the firstchannel is a first radial channel and the second channel is a secondradial channel axially spaced apart from the first radial channel,wherein when the valve is unactuated: (i) the annular groove forms anaxially extending flow passage that overlaps, at least partially, thefirst radial channel and the second radial channel of the pilot seatmember to fluidly couple the second radial channel to the first radialchannel, such that when the fluid force overcomes the biasing force ofthe setting spring on the pilot check member, the pilot check member isunseated and a pilot flow path is formed to allow pilot flow from thefirst port to the second port through the first radial channel, theannular groove, the second radial channel, the cross-hole of the pilotsleeve portion, and the cross-hole the solenoid actuator sleeve, therebycausing the piston to move axially and open a main flow path from thefirst port to the second port to relieve fluid from the first port tothe second port.
 20. The valve of claim 19, when the valve is actuated,the annular groove moves out of alignment with the first radial channel,thereby causing the second radial channel to be fluidly decoupled fromthe first radial channel, blocking the first radial channel, andprecluding pilot flow from the first port to the second port.